Often, those working in the construction industry, such as builders and carpenters, need to construct prefabricated items or structures from wood or timber. Pieces of wood or timber forming such items or structures were often secured one to another using fixings such as nails, screws or bolts.
Whilst screws and nails were useful for attaching small pieces of wood, one to another, the usual manner of securing larger pieces of timber together or securing timber to third party materials, for example of the sort used in frames and larger structures, involves drilling a hole through each material where they should be joined. There are then two traditional methods of securing the materials together:
Option 1—A metal bolt, usually made of steel, is passed through the hole, a nut and washer is then tighten onto the threaded end, so effectively clamping the pieces of timber or timber to a third party material together.
Option 2—A threaded rod is cut to the correct length to fit through the hole created, with a small excess on either side. A washer and a nut are tightened onto each end, holding the pieces of timber together, so effectively clamping the pieces of timber or third party material together.
These bolts/threaded rods were typically of a diameter between 8 mm and 20 mm.
Although this method was widely used, it suffered from several disadvantages.
The use of a ‘coach bolt’ in securing timber members has many drawbacks and limitations, namely:                1. It relies on the user to drill the correctly sized hole through the timber members. Due to the small head size in relation to the diameter size of the bolt, there is little tolerance for drilling an over-sized hole.        2. Due to the small surface area of the head to the bolt, it is usual for Building Control Officers to request the use of a 50 mm×50 mm washer.        3. It is a common occurrence for the bolt to turn within the timber before it is completely tight or has reached the correct torque.        4. It is also a common occurrence for the small head of the bolt to be pulled into the timber member, deforming the timber face, thereby reducing the effective structural depth of the timber as designed.        5. In the case of domed headed bolts the bolt makes it difficult to subsequently attach or fix finishing materials, such a plywood and plasterboard, as it is not possible to achieve a true level surface without remedial works being required.        6. There are instances which require the contractor to pass the bolt through the first member and then offer up the second member over the bolt. The second member pushes the bolt out of the first member adding to the frustration.        7. Due to the small surface area of the head to the bolt, it is difficult to achieve the correct torque to the nut without deforming the surface of the timber member. This is a particular issue when the head of the bolt is visible. It leads to an unsightly finish.        8. There is no facility to restrain the bolt in position.        
The use of threaded rod in securing timber members also has many drawbacks and limitations, namely:                1. Wastage is excessive and common due to the bars being supplied in set lengths. It is exceptionally unusual to use the entire rod.        2. When the rod has been cut, the thread becomes deformed making it difficult to thread the nuts.        3. In order to fix the rod in position, it requires two sets of nuts and two sets 50 mm×50 mm washers, which adds expense and is often awkward.        4. It is a common occurrence that when tightening one nut, the shaft or bar has a tendency to turn within the opposing nut, thereby winding the rod through the timber members.        5. There is no facility to restrain the nut or threaded rod in position.        6. It is an awkward and time-consuming activity for those working in construction, as they must tighten one washer and nut onto one side of the threaded rod, then hold it in place with a spanner whilst tightening a washer and nut on the other side resulting in continuous access being required to both ends of the bolt, using two separate spanners, in order to secure the fixing. Space constraints commonly experienced on construction sites often restrict the possibility of achieving this.        7. The nuts can become loose and may be lost, decreasing the likelihood of the fabrication staying together and potentially putting people at risk.        
Means of securing pieces of timber and other construction materials that require fewer parts are known in the art. For example, DE-A-3 133 638 (Bergner Richard GmbH) discloses a screw device with a head comprising a series of spiked teeth, which latch into the wooden material. However, the matter of the head of the bolt gouging into a work piece was not addressed.
Although the bolt described in DE-A-3 133 638 was an improvement upon existing methods, (because it required no nut or washer on one side of the work piece or building materials), the screw device disclosed made no attempt to further secure both ends of the bolt. The result was that despite a washer and nut being placed on a ‘blind side’, the bolt could still work loose. Furthermore, in many jurisdictions, building regulations require the bolt to fully pass through the surface it penetrated and to be secured by a nut. As such, in many situations, the screw device does not always meet building regulation standards.
Another example of a screw device is disclosed in UK Patent GB-B-2 372 304 (Rendell). A bolt with a hexagonal head is disclosed. The bolt has spikes formed in the head of the bolt. The spikes engage a surface and impede rotation of the bolt, for example when being tightened from a blind side of a work piece.
French Patent Application FR-A-997085 (Dehousse) discloses a bolt which has a notch formed at its end. This would not have been appropriate for joining two timber work pieces.
The present invention arose in order to provide an improved bolt which is quick and simple to install, cheap to manufacture and does not suffer from the aforementioned disadvantages of turning whilst being tightened, falling out of timber due fabrication, pulling through timber, working loose over time, as well as providing a safer way of joining timber pieces together or a timber to another structure, without the risk of bolts and nuts working loose.